Explosive pyrotechnic complexes of ferrocene and inorganic nitrates

ABSTRACT

NEW EXPLOSIVE AND/OR PYROTECHNIC COMPLEXES ARE FORMED FROM FERROCENE AND ITS DERIVATIVES WITH SPECIFIED INORGANIC NITRATES, I.E., MERCURIC, CERIC, AND CUPRIC, EACH OF THESE NITRATES KNOWN GENERALLY AS BEING INSENSITIVE TO SPARKS OR IMPACT.

United States Patent Office 3,673,015 Patented June 27, 1972 3,673,015 EXPLOSIVE PYROTECHNIC COMPLEXES OF FERROCENE AND INORGANIC NITRATES Gilbert P. Sollott, Plymouth Meeting, and William R. Peterson, Jr., Levittown, Pa., assignors to the United States of America as represented by the Secretary of the Army No Drawing. Filed May 23, 1969, Ser. No. 827,161 Int. Cl. C06f 3/06 US. Cl. 14929 25 Claims ABSTRACT OF THE DISCLOSURE New explosive and/or pyrotechnic complexes are formed from ferrocene and its derivatives with specified inorganic nitrates, i.e., mercuric, eerie, and cupric, each of these nitrates known generally as being insensitive to sparks or impact.

The invention described herein may be manufactured, used and licensed by or for the Government for governmental purposes therein without the payment to us of any royalties thereon.

This invention relates to explosives and pyrotechnic materials and more particularly concerns ferrocene and its derivatives to form explosive and/ or pyrotechnic complexes with selected inorganic nitrates.

Commonly used prior art primary explosives leave something to be desired. For example, as an explosive ingredient, ammonium nitrate is extremely hygroscopic. Mercury fulminate as an ingredient in priming compositions is undesirably sensitive to light and elevated temperatures. Small quantities of mercury are formed which produce amalgams with copper, brass, and bronze, leading to metal failure. Lead styphnate, which has replaced mercury fulminate as an ingredient in detonators and primary compositions, is a relatively poor initiator when compared with other primary explosives. Other primary explosives sufier drawbacks which prevent their utility from being completely acceptable for military applications.

and pyrotechnic complexes from ferrocene and its derivatives with specified nitrates, the complexes having a wide range of controllable characteristics.

Other and further objects of the invention will become apparent as the invention is further described hereinafter.

In accordance with the above objects, explosive or otherwise energetic complexes are formed from ferrocene and its derivatives on the one hand and mercuric, eerie, and cupric nitrates on the other. The structure of the ferrocene reactant (bis-cyclopentadienyliron) has been reported in the literature by Wilkinson et al., Journal of the American Chemical Society, vol. 74, page 2125 (1952), and may be described as a sandwich-type structure having an iron atom between two staggered cyclopentadiene .rings 1 as shown below:

Some of our complexes are primary explosives and are useful in igniting charges and detonators, and as ingredients in priming compositions and pyrotechnic mixtures. The complexes will be prepared thus:

A solution of ferrocene or ferrocene derivative in a solvent such as benzene, methyl or ethyl alcohol, or ether is slowly added, with stirring, to a filtered solution of the inorganic nitrate (drying unnecessary) dissolved in excess in methyl alcohol, at room temperature, usually causing precipitation of the complex. The product is collected on a filter under suction, without delay, and washed with small quantities of methyl alcohol and benzene in succession, then air dried. In some cases, solvents such as ethyl or isopropyl alcohols, acetone, or tetrahydrofuran may be substituted for methyl alcohol.

The following table lists complexes prepared by the above method:

TABLE L-EXPLOSIVE COMPLEXES OF FERROCENE AND ITS Light-blue Yellow-orange... do

a Hammer-blow applied. d FcH=Ferroeene.

Sensitive.

b Tesla coll used. Complex contacted with hot plate. 9 Fc=Ferrocenyl=G H FeC H I E=Explodes. K

h -=Insensltive.

An explosive complex (Item No. 6, for example) is obtained from Hg(NO and Fe P upon adding a benzene solution of the latter to a methyl alcohol solution of the former, employing the reactants in a range of molar ratios of about 3 to 1 up to about 20 to 1. For the compounds listed in Table I, the ratios will vary from between about 1 tol to about 20 to 1.

'"The mercuric nitrate and Fe P in a 1:1 molar ratio gave a product which could be ignited with a spark, but could not be detonated by impact'with a hammer. With a 2:1 molar ratio, a mixture of spark ignitable product and hammer explodable product was obtained. When the ratio was increased to 3:1, the product obtained was readily exploded. With ratios greater than 3:1, higher yields of the explosive product were possible.

In the practice of our invention, the weight of Hg(NO will be at least 10 times greater than that of the ferrocene derivative, yielding the complexes substantially quantitatively. In the case of FCgP and Hg(NO the molar ratio will be about 18 to 1, the Hg(NO being in excess. The excess Hg(NO after precipitation of the complex, may be used in forming more complex from additional ferrocene derivative.

EXAMPLE I A benzene solution containing 12 g. Fe P was slowly added, with stirring at room temperature to a solution containing 120 g. Hg(NO prepared by dissolving the nitrate in excess methyl alcohol and filtering oif the insoluble solids. 31.5 g. of complex precipitated. After being washed with methyl alcohol and benzene in succession, a small sample was dried 1 hour at 100 C. in vacuo which produced in 6.7% weight loss. Based on a quantitative precipitation of all the Fe P, the apparent molar ratio of Hg(NO to ferrocene derivative in the complex was 4.5.

EXAMPLE II The procedure set forth under Ex. I was used, the compounds of Table I, Item No. 9, yielding:

EXAMPLE III The procedure set forth under Ex. I was used, the compounds of Table I, Item No. 3 yielding:

FeCN

In the latter two examples above, when the weight of the Hg(NO was times the weight of the ferrocene derivative, the molar ratio of the reactants employed was With alkyl or aryl substituted ferrocenes, addition of ether or benzene was necessary to cause the complexes to separate from solution.

Ceric ammonium nitrate was used as the source of ceric nitrate in the complexes shown in Table I. It would seem that the complexes contain no ammonium since NH NO itself yields no complex.

Complexes of mercurous nitrate with Pe l and F3PO were found to be impact, spark, and heat sensitive, but without explosion capability under a hammer blow, contrary to behavior when mercuric nitrate was used. Complexes prepared from triphenylphosphine and mercuric or mercurous nitrates were completely inactive even though mercurous nitrate itself is known to explode when heated to boiling. It is apparent therefore that complexing of the inorganic nitrate to a ferrocene species is essential and that the activity exhibited by the complexes cannot be at tributed to mercurous nitrate per se. Thus, in the case of complexes with mercuric nitrate, activity cannot be attributed to reduction of mercuric to mercurous. (The blue color of some of the complexes tabulated in Table I may be due to oxidation of ferrocene to ferrocinium and tend to indicate reduction of mercuric to mercurous.) Substitution of ceric for mercuric further substantiates the above. Mercurous nitrate is not sensitive to impact with a hammer, nor is it spark sensitive. Physical mixture of mercurous or mercuric nitrate with ferrocene desivatives are not active.

The product obtained from Cu(NO and Fc PO gives a pyrotechnic display consisting of rapid sparking when contacted with a hot plate. With cobalt and ceric nitrates, a weak flash is observed, while mercuric nitrate yields quick, bright flashes. When compared to Fc PO, bromoferrocene and diferrocenylmercury produce superior fiash characteristics, i.e. brighter flames. Such materials may find use as ingredients in pyrotechnic compositions and as secondary explosive ingredients. Except for ammonium nitrate, inorganic nitrates per se do not flash on a hot plate. Ammonia nitrate, however, requires a much higher temperature than do our complexed nitrates before flashing occurs.

Item No. 16, complex FeSi(C H OH-xHg(NO first precipitates as a red solid on forming, then becomes a blue-black taify. In the latter form, the substance is useful as a single-ingredient fuse that can be applied with a brush. Upon standing, the tafIy-like material appears to undergo polymerization to a brittle glass, and may 'find use in high-energy materials that have been cast or molded.

We claim:

1. A new composition of matter comprising an explosive pyrotechnic complex formed by ferrocene and derivatives of ferroccne with an inorganic nitrate selected from the group consisting of mercuric nitrate, mercurous nitrate, ceric nitrate, and cupric nitrate.

2. The composition of claim 1 wherein said complex is ferrocene -xHg(NO 3. The composition of claim 1 wherein said complex is bromoferrocene xHg (N0 4. The composition of claim 1 wherein said complex is cyanoferrocene-xHg(NO 5. The composition of claim 1 wherein said complex is butyl ferrocene -xHg (N0 6. The composition of claim 1 wherein said complex is diferrocenylmercury xH g (N0 7. The composition of claim 1 wherein said complex is triferrocenylphosphine-xHg(NO 8. The composition of claim 1 wherein said complex is diferrocenylphenylphosphine xHg (N0 9. The composition of claim 1 wherein said complex is ferrocenyldiphenylphosphine -xHg (N0 10. The composition of claim 1 wherein said complex is triferrocenylphosphine oxide -xHg(NO 11. The composition of claim 1 wherein said complex is trifcrrocenylphosphine sulfide-xHg(NO 12. The composition of claim 1 wherein said complex is triferrocenylphosphine selenide-xHg(NO 13. The composition of claim 1 wherein said complex is benzenel,4-bis(triferrocenylphosphineimine) xHg(NO 14. The composition of claim 1 wherein said complex is diferrocenyl-N-N-diphenylphosphinic amide xHg(NO 15. The composition of claim 1 wherein said complex is diferrocenylphosphinic acid-xHg(NO 16. The composition of claim 1 wherein said complex is ferrocenylphosphinic acid -xHg(NO 17. The composition of claim 1 wherein said complex is fe rrocenylidphenylsilanol -xHg (N0 18. The composition of claim 1 wherein said complex is diferrocenyldiphenylsilane xHg (N0 19. The composition of claim 1 wherein said complex is ferrocenyldiphenylarsine xHg (N0 20. The composition of claim 1 wherein said complex is ferrocene-xCe(NO 21. The composition of claim 1 wherein said complex is triferrocenylphosphine xCe(NO 22. The composition of claim 1 wherein said complex is triferrocenylphosphine oxide -xCe(NO 23. The composition of claim 1 wherein said complex is triferrocenylphosphine oxide-xCu(NO 24. The composition of claim 1 wherein said complex is triferrocenylphosphine xHgNO 25. The composition of claim 1 wherein said complex is triferrocenylphosphine oxide-xHgNO References Cited UNITED STATES PATENTS 5/1963 Dubeck 149-109 X 1/ 1965 McElroy et a1 149-45 X 5/ 1967 Pruett 149--109 X 9/1967 Neuse 149--109 X 6/ 1969 Sayles 149109 X 4/1970 Deifener 149109 X CARL D. QUARFORTH, Primary Examiner S. J. LECHERT, JR., Assistant Examiner U.S. Cl. X.R. 

